A new study by researchers at Weill Cornell Medical College and New York Blood Center found that new screening strategies for preventing transfusion-transmitted babesiosis (TTB), the most common red blood cell transfusion-transmitted infection in the United States, would avoid additional cases and are cost-effective compared with many other blood-supply screening tests. The results apply to geographic regions, such as New York State, where Babesia is highly prevalent, can be lethal in those with compromised immune systems, and is frequently transmitted through a tick bite.
The study, published online Nov. 19 in Transfusion and led by Assistant Professor of Medicine and Assistant Professor of Public Health Dr. Matthew Simon, employed a computer simulation model to determine how the new blood-supply screening tests for Babesia would affect transfusion recipient and donor quality of life and societal costs. The authors found that screening of blood donors in endemic regions could avoid approximately three cases per 100,000 red blood cell transfusions. In these states, up to 2 percent of blood donations can contain antibodies to Babesia, and infections occur anywhere from one in 20,000 and one in 100,000 transfusions.
There is no Food and Drug Administration (FDA)-licensed screening test for Babesia, but several tests are under investigation and under consideration for FDA approval. The current method of screening is to ask blood donors if they have a history of babesiosis on a pre-donation questionnaire, which is largely ineffective in identifying infected donors. The Centers for Disease Control and Prevention has documented at least 122 TTB cases between 2000-2009, but the actual number of cases is higher due to lack of recognition and under-reporting. In New York City, between two and seven TTB cases are reported annually. Babesiosis is associated with a mortality rate of 5 to 20 percent.
The study found the cost-effectiveness ratio of antibody testing compared to the current method to be $730,000 per quality-adjusted-life year (QALY) saved. This cost-effectiveness ratio is less attractive than for many commonly accepted medical and pharmaceutical interventions (which range from $50,000-100,000/QALY), but compares favorably to other currently implemented blood-supply screening tests such as for West Nile virus and Chagas disease.
In March, Weill Cornell hosted a forum that called attention to TTB and other tick-borne diseases, and advocated for further research on the problem.
"I hope our results will aid clinical leaders and policy makers in addressing the appropriateness of laboratory-based screening of the blood supply for Babesia in various geographic regions of the United States when a licensed test is available, and support its implementation in highly endemic areas," Dr. Simon said.